The banking industry has for many years imprinted magnetic ("MICR") characters upon documents (e.g., bank checks) so as to provide document-identifying information which can be visually read by humans and also automatically read by machine. The characters are printed on the document using magnetic ink (ink containing small magnetic particles) in an industry standard font configuration (specified, for example, by the latest revision of specification ANSI X3.2 entitled "American National Standard Print Specifications For Magnetic Ink Character Recognition" published by the American National Standards Institute, Inc. or by other MICR fonts, such as CMC-7). Briefly, for the E13-B font defined by ANSI specification X3.2, each "MICR" character is established by ink deposited in specified cells of a 7.times.9 matrix of discrete squares each 0.013 inches wide. The deposited ink pattern is visually recognizable by humans (e.g., as the numerals 0-9 or as special characters).
In addition, the amount of ink deposited in the various "columns" of the matrix is used by magnetic recognition systems to automatically identify the character. By first magnetizing these characters and then moving them past a magnetic read head, a waveform may be generated representing the rate of change of magnetic flux with time (d.phi./dt). The resulting electrical waveform indicates change in the amount of magnetic material beneath the read head as the medium bearing the characters moves past the head. Since the MICR character set is defined such that the combination of magnetic material amounts in the seven "columns" of a given character is unique, a corresponding unique waveform is developed for each character by the read head. The characters may be distinguished from one another (using appropriate recognition circuitry) by analyzing this resulting waveform.
Once the first part of a character passes the magnetic read head, it is important for the MICR recognition system to separately capture signals representing each of the following seven 0.013 inch long "segments" of the character--even though the position of the characters with respect to the document leading edge can (and typically does) vary from one document to another. This strict requirement has led others in the past to require the document to move past the read head at a fixed, constant and predetermined velocity--and to synchronize the recognition circuitry with a fixed frequency clock timing signal (e.g., produced according to the resonant frequency of a quartz crystal). While this solution is satisfactory for some applications, it requires an expensive and accurate mechanical document conveyance system (e.g., using a synchronous motor). The requirement of maintaining constant document velocity is, of course, impossible to meet in a hand-operated MICR recognition system.
Because of these (and perhaps other) problems, the conventional wisdom in the MICR field has been that a small, inexpensive and accurate manually operated magnetic check reader would be impossible to produce. Those recently designing inexpensive check readers have therefore used optical character recognition techniques. This approach has several disadvantages, however. One of the reasons banks initially adopted magnetic character recognition techniques is because magnetic reading of MICR characters is generally unaffected by folding, markings, and other mutilation of the document. Another reason is to help ensure check authenticity--because a photocopy of a check does not bear magnetic ink, the failure of a magnetic reader to recognize characters on it would indicate document inauthenticity. A magnetic character reader is in many cases capable of accurately reading characters which are incapable of being read optically, helps prevent the passing of "bad" checks, and has other advantages as well.
A particularly useful system which permits relaxation of the requirement of constant document velocity and also permits characters to be magnetically read with great accuracy is taught in U.S. Pat. No. 4,134,355, which issued to Robert M. MacIntyre on Mar. 6, 1978 and is commonly assigned with the subject application. MacIntyre's preferred embodiment derives a train of pulses from a timing means mechanically coupled to relative movement of the document with respect to the magnetic read head, and captures signals produced by the read head in response to pulses of the pulse train. MacIntyre's approach is quite significant--especially in view of the significant cost advantages provided by relaxing the constant document velocity requirement.
The present invention utilizes concepts disclosed in the MacIntyre patent to provide a low cost compact magnetic character recognition system which magnetically reads characters imprinted on documents as the documents are manually scanned by hand past a reading station (rather than having the documents automatically fed via driven rollers, vacuum belts or other like equivalent means). The present invention permits MICR systems to be employed cost effectively in many environments (e.g., at the point of sale and as part of bank teller terminals) which do not justify the expense (and/or cannot accommodate the size) of prior art magnetic check reading devices.
This advantage is obtained, according to the present invention, in a device which includes a slotted path sized and configured to accept the document as it is manually conveyed past a magnetizing station and a magnetic reading station. The slotted path is dimensioned so that a region of the document is exposed to permit it to be grasped by a user and manually conveyed past the magnetizing and reading stations.
An endless idler member having a friction surface is journally mounted such that at least a portion of the friction surface is substantially tangentially oriented relative to the slotted path. Means are provided in confronting relationship to the idler member which define a nip in the slotted path through which the document passes as it is conveyed and which urges the document into frictional engagement with the idler member's friction surface. This frictional engagement beneficially causes the idler member to rotate in response to relative movement between the document and the reading station.
An encoding disc is positively driven by the idler member rotation. Timing means associated with the encoding disc generates a pulse in synchronous response to document movement. These pulses time the collection of samples of the waveform produced by the reading station in order to identify characters on the document.
In accordance with another aspect of the invention, a MICR recognition circuit is provided which can accurately recognize the characters of a document regardless of the direction in which the document moves past the read head (e.g., right-to-left or left-to-right). Thus, a user need only orient the document so that the MICR characters pass by the read head--the direction the user moves the document past the read head being unimportant.
The preferred embodiment of the present invention can be economically incorporated into point of sale and many other types of systems. For example, each cash register in a retail store can be provided with a hand-operated check reader as well as a hand-operated credit card reader. Checks presented for payment can be automatically read and checking account numbers rapidly verified to provide the retailer with assurance that the check is "good". Electronic funds transfer (EFT) could even be used to debit the appropriate checking account--thereby reducing the volume of checks which flow through the payor bank.
Other aspects and advantages of this invention will become more clear after consideration is given to the detailed description of the preferred exemplary embodiments which follow.